1. Field of the Invention
The present invention relates to an analog electronic timepiece that receives radiowaves from positioning satellites to acquire date and time information and positional information, and a method of controlling the movement of the hands of the analog electronic timepiece.
2. Description of Related Art
Conventionally, electronic clocks (atomic clocks) have been known that receive radiowaves from satellites (positioning satellite) in global navigation satellite systems (GNSSs) to correct the date, time, and position (time zones) and determine positions. The received radiowaves are usually processed with a module that comprehensively performs reception, data deciphering, and calculation of the positional information. The processed date and time data and the positioning data are sent from the module to controllers of electronic devices.
Accurate data on date, time, and position can be acquired from the radiowaves sent from the positioning satellites usually in the form of 30-second data sets from four or more positioning satellites. Unfortunately, the reception time varies depending on conditions, such as information on the predicted orbits of the positioning satellites and obstacles blocking the radiowaves from the positioning satellites. Various techniques are known for the calculation of date, time, and position through a shorter reception time so as to reduce the power consumption and dimensions of the clocks.
An electronic clock usually displays the reception state of radiowaves during the reception of radiowaves. If the reception time varies as described above, the user of a portable electronic timepiece will not know how long to remain in a stand-by mode for the maintenance of satisfactory reception and the acknowledgement of reception results. Japanese Patent Application Laid-Open No. 2009-236560 discloses a technique for the prediction of the remaining reception time on the basis of the tracking state of the radiowaves from the positioning satellites and the content of data being received, and displaying the predicted remaining reception time.
Another technique is known for analog electronic timepieces that display time with hands that point to marks provided at predetermined hand positions to indicate the reception of radiowaves. If the reception of radiowaves is completed in a short time, the reception will finish while the hands are still in motion. The hands must return to the original positions before the hands reach their destinations, resulting in redundant movement of the hands. Japanese Patent Application Laid-Open No. 2011-163912 discloses a technique for an analog electronic timepiece to move a hand in advance to a position indicating the reception end time predicted on the basis of the delimiter in the format of the received data, and pause the movement of the hand.
If the hand of an analog electronic timepiece stops at different positions, the user cannot readily confirm the reception of radiowaves by the electronic timepiece. Moving a hand during reception requires a sequence of many control commands involving the movement. This may cause a delay in the acquisition timing of data, and thus, a delay in the acquisition of the date and time, resulting in low accuracy.
The present invention provides an analog electronic timepiece that can reliably inform a user about being in a state of receiving radiowaves without lowering the accuracy of the date and time data acquired in the form of radiowaves, and a method of controlling the movement of a hand of the analog electronic timepiece.